So, in any case, you've got to have an idea of how fast a SSD is, and the difference it makes to the way you work with your computer. For instance, take this example:
[video=youtube;rzxDAL_bwOo]http://www.youtube.com/watch?v=rzxDAL_bwOo[/video]
An SSD turns everything on its head, and gives even an old laptop a new lease on life - suddenly that Core 2 Duo 1.6Ghz flies even while on battery power. But there's three things you need to understand:
1) SSDs require a motherboard with ACHI and Trim support. Trim allows Windows to reclaim lost space from the cell blocks used when deleting data. An old theory was that a motherboard without Trim support, and a user with an average data use of 10GB a day would deplete the available drive space on a 64GB SSD in two years - today that's no longer an issue, but it something to think about when using a much older rig.
2) There is a slim chance that data recovery on a crashed SSD is possible, but mechanical drives are much better with attempts at recovering data on a failed platter. Since the drives are essentially large flash devices, its better to keep all non-essential data off the main drive, and to regularly back up your files and folders in case of a failure - this really is no different to the best practices that should be employed if you use a mechanical drive.
3) SSDs have lifespans that can equal and even best the most expensive hard drives on the market. I struggle to find links now, but both Google and Amazon have moved to SSD storage for their data servers, and they've reported no visible change to the amount of drives they've had to replace, but their operational costs are lower, and speeds are massively increased.
Three articles from Tom's that you should read:
Could An SSD Be The Best Upgrade For Your Old PC?
Investigation: Is Your SSD More Reliable Than A Hard Drive?
Best SSDs For The Money: July 2011
Just a bit worried about the shorter life span
As previously said, there's no more danger running an SSD than there is with running a HDD.
But is a 64GB SSD enough?
Cause I think OS us up like about 20GB rights?
So that means you only have like 35GB to work with..
enough?
From what I've experienced across my desktop, work desktop and personal laptop, most full Windows installations take about 25GB of free space if you're running a 64-bit Windows 7 Ultimate install with Office and a couple of other things installed. A 64GB SSD should be fine for most users.
when you used to copy on a SSD then when you work with your normal drives they seem so slooooooow
not big enough.. 
